+ Intuitive controls
+ Weapons work well (not just hitting enemies, but also destroying their projectiles)
+ Relaxing music
- Slugs are bombs; I don't kill them, they explode. (Who knew?)
+ Leveling up. The point above was missing because of this, but I'm already strong and experienced HD
+ Slugs are bombs, yes, that's also a plus, it's the risk of killing them while they're detonating