Enemy bots offer more of a challenge as they are better armed and stand at roughly the same size as your Slave. There are few hints of an AI at work, as enemies usually fire at you from fixed positions or make beelines for you. This isn't as disappointing as it might sound since enemy units rarely survive more than a few shots anyway. The most interesting interludes are definitely the boss fights that you must engage in from time to time. The bosses have devastating attacks and these battles are just about the only time when you need to think before you shoot.
Boss fights offer unique challenges.
The power-up system is very basic. Each of these weapons can be improved by picking up weapon upgrades scattered throughout the levels. You also need to constantly replenish your ammunition. This rarely becomes challenge since reloads for each of your weapons are found in abundant amounts. But you do have to monitor your supplies closely, since running out of ammo can put you in an awkward situation, to say the least.