It turns out that there are some exploits involving the Miracle spell.

1. There is no minimum level required to cast the spell. (This is unlike Wizardry, where the corresponding spell required you to be at least level 13 to cast.) Therefore, you can have a character who just class changed and is still level 1 cast the spell. Also unlike Wizardry, level 1 characters can't be level drained, so you can avoid the spell's biggest drawback this way. After the battle, you will get a message saying that the character lost 0 levels, but there will be no other effects. (In particular, you don't lose HP or gain/lose MP.)

2. When you are level drained, the game recalculates your MP. If your level in your class is too low to cast a spell level that you know, you will get 1 MP per spell to a maximum of 3. This means that if your Mage just reached level 13 and learned all three 7th level spells, her level 7 MP will increase from 1 to 3 if she casts Miracle. Wish you had mare than one cast of Diomente right now? Cast Miracle and now you have 3.

3. One other side effect of being level drained: you get your MP back. In the final bonus dungeon (where Diomente can't be used) and foolishly used up all your Bishop's level 4 MP? Cast miracle and you now have your MP back, allowing you to cast Honey Restorer. (Of course, you will lose a level and not have enough experience to regain it, so you won't have that spell for your next trip.)

One more thing: Unlike in Wizardry, teleporting out of battle after being level drained (or casting Miracle) will not allow you to avoid the experience loss.

I'd call pt.3 a clever use of game mechanics. Pt.2 is definitely a bug, but it has quite a limited time of usefulness.

Off-topic: how did this thread get 2 pages?

Edit: strange, now this thread looks as it should.

Actually, I'd argue Pt.2 is not a bug, but rather a quirk in the way the game calculates MP.

If you are in a casting class, you get MP according to a table. If you just gained access to a new level of spells beyond 1st, you will only have 1 MP of this level. (If you unpack the .bra files, the table is contained in SPMP.csv.)

If you are not in a casting class, you will get 1 MP per spell known, with a maximum of 3.

So, a level 13 mage who knows every 7th level spell will have only 1 MP, but a level 1, say, cleric knowing the same spells will have 3 level 7 mage MP. In otherwords, you actually game MP when you change class in this case.

When a level drain occurs, the game needs to recalculate MP. The reason you get 3 level 7 MP is that the game needs to account for the case where you knew the spell from a previous class or due to being a spirit pact character. (Case in point: Ghost Mage becomes a mage who already knows 2 7th level spells.)

Another oddity: a former caster learns new spells at the levels of a pure caster (assuming she already knows at least one spell of that level) unless the character is in a class that learns the spells naturally. For example, a spirit pact Nine-eyes (brawler, knows Feireed) can learn other 6th level cleric spells at level 11, but a spirit pack Dragon Lord (lord, knows Elnam) has to wait until level 14.

One more word of warning for Miracle users: If you have lost vitality through leveling and are then level drained, you may lose a lot of HP. My hobbit thief Sherra lost a couple hundred hit points after using Miracle with 15 Vitality. (Two Protectorates and she gained 198 HP when regaining that level (from 97 to 98).

Some of the mechanics of the game are just not well behaved. (Another good example is Song of Healing on characters with less than 20 max HP)

Ha, one of things I learnt in this kind of games is always reload when you lose stats on level-up and always reload on level drains. otherwise it might lead to situation when Continuing is Painful.

Song of Healing on characters with less that 20 Max HP is rather a small hand-holding moment for low level characters. I wouldn't be surprised if low level characters also get invisible bonuses to chance to hit, because I just can't see how my party could even kill something at lv.1, as their rate of misses at lv10-11 in 1st dungeon was abnormally high, and they were missing a lot on monsters with 8-10 AC.

The problem with reloading everytime you lose a stat at level up is that it's not practical when gaining lots of levels. The thief in question had just gained 32 levels after one fight with Greater Demons. (Let them keep calling for help, then when done, put the last one to sleep and have everyone else run away so they don't get a share of the experience.) Reloading after every stat loss is not feasable.

Sometimes, it is worth taking a level drain if it means killing a boss or contracting a hard to contract monster.

As for to hit chances, in classic Wizardry, fighter types and clerics only gained +1 to hit every 3 levels. (For mages, thieves and bishops, it's +1 every 5 levels.) In other words, you need to gain a lot of levels to get your hit chance up a noticeablel amount.