Black space (the tiles you haven't explored yet), is one of your most valuable resources : every tile you explore restores some of your mana and some of your health. So it is important to keep some unexplored areas to heal between fights.
However, you need to explore enough to find suitable monsters to fight, bonus glyphs... Thus, an important part of the game is to keep the balance between pure exploration and regeneration, and to use efficiently that black space.
Hero regeneration rate
Most class recover for each uncovered tile :
- 1 Hp per level (so 4Hp/tile if you are level 4)
- 1 mana per level, whatever your level is.
Use that to explore wisely : if you are trying to regenerate for a fight, there is no need explore 4 tiles, when 2 will be enough to fully heal.
Keep in mind that monsters will also regenerate (1 HP per monster level. So a level 8 monster will recover 8Hp per turn). So you will often want avoid exploring during a fight, and thus fully recover health and mana before starting.
However, note that you recover Health + mana, while monsters only recover health. Use that at your advantage !
In some case you will be able to damage a monster quicker than it heals (regen-fighting). It might look grand to get some bonus XP. However, note that in the end you would have to hit him more often, and would thus have used more health. So, keep in mind that regen-fighting is less efficient in terms damages per black space : make sure that the bonus XP is really worth it.
Spare mana/health usage
If you wish to fully recover before a fight, you will often have more health than or vice-versa. It would be silly loosing it, so always try to use the spare health/mana for something. There are plenty of opportunities to invest spare mana (monster slowing, giving burning effect, getting physical resistance from wall crunshing,...), so make good use of them. Spare health might slightly trickier to invest wisely as monster will heal at the same time as you do. But before fully recovering mana, you can also double check that you really need it !
If you can save all mana/health, don't worry too much. You often won't have a choice or have something to do.
Black space positioning
You will sometimes need to explore just 1 or 2 squares during a fight, to recover the right amount of health to give the final blow, without allowing the monster to heal too much. So it is always a good idea manage such accessible black tiles during your exploration.
The high mana/health trap
Keep in mind that exploration refills a fixed quantity of health and man per tile. You will to explore many more tiles to fully recover a big health or man bar. While this is useful to fight tough monsters, you maybe don't need to fully restore before next fight (especially if it will lead to a level-up, and can't use the spare mana/health)
Exploring the inaccessible
There will often be tiles which can be explored by normal means. You can still exploit them with LEMMISI (explores random tile) or BLUDTUPOWA (explores nearby tiles). Destroying walls is another way to reach them.