I've played this build all the way through the game and it seems to work very well.
1st Confusion
2nd Crystal Ball
3rd Teleport
4th Purify or Crystal ball
5th Purify or Crystal ball
6th Purify or Crystal ball
Mine Level 1&2.
Wait to spend your skill points until you have 2 points, then get Confusion and Crystal Ball together. I often wait until I get three points then spend them on the first three in one hit. This can be a challenge, but the rewards for getting through the first 2 levels with no skills are reflected in cautious gameplay and better strategy. A cautious and patient approach will set you in good stead for the later levels.
Finish the challenges to get a mana potion when you start and drink this as your first action. This will increase your damage output with a wand.
The first level of Bandit hole should present no problem with critters taking no more than 2 shots to down.
Second level challenges will be primarily the Gypsy, if you've already spent your 2 skill points and she puts you in a bad place away from the crystal ball then you could be in a world of hurt. It is best to wait until you have the first three skills to spend, so you always have teleport available, just in case.
Mine Level 3&4
Assassins will be your main challenge this level. If you have a sword and better armour you could go toe to toe with them, one or two hits will down them often enough. If no sword then there are a couple of strategies available.
The straight switcheroo – make a crystal ball appear beside you. This will draw an attack from the Assassin, which if you've found leather armour should have a good chance of missing. Then switch places with the ball which does not draw an attack and let the ball do its thing.
The one hop stop – If you are really low on hit points and have 16 mana left you can telehop back a place then put a ball between you and the assassin.
If you're low on both mana and health then hitting it with confusion and running away might work out…
Archers and gypsies will be painful too and a bit of telestabbery should sort them out. generally try to engage front opponents with the crystal ball then go to with wand or telestab. With this build there is no mana gain from telestab, but curtailing damage intake is good for the health.
The next skill choice is a tough one. If your rogue is underarmoured or taking lots of damage then purify is a natural choice. However taking this will reduce your damage output considerably, both in terms of reduced mana for the wand, and the second level in crystal ball is a marked increase in your offensive power. The balls are tougher, do more damage and last longer, plus you can get two of them. Good for when you get swamped in a corridor.
Melee combatants like black hat cowboy, bats, rats etc should all be fairly easily dealt with by placing a ball between you and going to with the wand. It can be a good idea to take a step back from the action, to prevent accidental swapping with the ball, and when it fades enemies can sometimes get the jump on you.
Level 4 presents the challenge of the Robot. This is very easily dealt with by judicious use of teleport then some telestabbery.
Genie.
You should have saved your robes for this encounter, if you picked up some other armour.
Make the Genie appear, kill the first beetle, then bust his lantern apart. From here you can either jump back and go farming or rest in the nook at the back of the room.
Equip a melee weapon, make a ball appear to deal with the beetles then take 2 telejumps next to the Genie. While the crystal ball is keeping your back clear of beetles whack away at the Genie. If you have purify and enough mana it can be a good idea to cast this before going into melee.
Once the Genie is dead, collect potions and drink them until you have at least 3 mana potions. The three Mana potions are your Satan killers. Don't have less than 3 mana potions for Satan. Keep more mana potions if you like, but yellow potions and ginger breads will suffice for mana gain during the next levels.
Dungeon Level 1&2
These levels are fairly easy when following some basic strategy.
Always interpose a ball between you and opponents.
If a room has a majority of ranged attackers block it up with a ball, then put another amongst the enemy then duck away to wait and heal.
If presented with a majority of melee attackers set up a ball then zap away with the wand.
Confusion can be handy for ghosts or bone archers, but often I would rather spend 2 more mana and put a ball next to them.
Robots on this level are just as easily dealt with as the ones in Bandit 4.
Dungeon 3&4
By now hopefully your rogue has level 3 in Crystal ball. Three balls on the field can be devastating to a large group of enemies, although I rarely use more than 2 at a time to conserve mana. A level 3 crystal ball should dish out around 20-30 points per hit and if you are providing wand assistance you can add another 8 – 15 per turn.
Bone demons and vampire bats are tricky and can outmanoeuvre your crystal balls. You should collect and save nets for these last two levels to trap wily critters and let your balls bash them. This not essential and it is possible to lure them in to combat, but it does make things a lot easier.
Knights will stun your ball and slow down the rate at which you can kill them. More a nuisance than a real threat.
Killing Satan
Swap out one of your quick items for the three mana potions you've been saving for the job.
Change armour to Robes if you want to, add any extra magic resitance items if you have them.
Check out what Quabbus has for sale.
Approach Satan.
Throw three mana potions.
And Hurrah! Satan is dead!