For upgrade guide and boss stage, please refer to another game guide: Ultimate DED Guide from Hydrus BlaZe. It helps me a lot in hard mode.

I would help in dealing with normal stages, since it is more difficult and made me headache :-p

- Concentrate to kill one enemy is better than just spam your bullets on all of them
- Kill one type of enemies is better than let them shoot you in different distances
- "Stand and kill one then walk away" is the key
- Give yourself time to reload for next wave
- "Shake the enemies" to buy more time and save space to move

- For each wave, keep one grenadier (or two, if necessary) in the field until you clean out other guys
- Purpose: Let yourself fully reload for next wave
- Details: Relatively grenadiers and shotgunners are safer because they act slow. They need half second to target you and half second to shoot. When grenadiers shoot, the sound effect will alert you first. Your eyes can concentrate on closer enemies. Usually I would walk closer rather than run away, because you can choose to shake other guys or run (more choice is better than hit the wall fast). However, try to NOT let grenadiers shoot.

Thanks, grenaders. You screw up your whole gang :-)

- Keep one shotgunner instead of grenadier if you die more than 3 times
- Purpose: In some stages (one or two only) there are too many "fat" pistol guys mixing with shotgunner. You need to shoot and run rather just spamming bullets. In this situation, grenadier focus you to keep running and it is danger that pistol guy will take you out when you hit the wall. So, grenadiers become your first priority.
- Detail: Shotgunners need to walk close to you so you have more time to react, but they block your shooting range. Plus, you may need to dash sometimes, and it is danger if there is other enemies are coming for you.
- The best timing to kill: When you are going to hit the wall, shake them into a group (they will be closer to each other) then dash. Walk away until other guys are closer to you (Shotgunner walks slower). Bang! Kill somebody now.

- Uzi or pistol first doesn't matter, but instance kill is important (don't wait for critical damage in hard mode)
- "Stand and kill one" each time, then run away
- Always know how many bullets load in your gun. It is the key of the game.
- Purpose: Grenadier only shoot you when they keep enough distance from you. So you can choose to charge to them and they run, or run away to buy more time. Other enemies will walk closer to you, so you can easily deal with them

- You can shake them to avoid attacks: Come close, walk away a bit, come close, walk away a bit.... etc.
- Don't rely on dash unless it is necessary. It takes time to reload, and sometimes out of control. Your target: dash only when you hit the wall

Personally I like to keep 2 or 1 grenadiers, rather than shotgunners, because when they run away from you and hit the wall, they will bounce and run again. Your eyes can take some rest for the next battle. Plus, grenadiers will not block other enemies.

Hope I can help you. English is not my first language, so please forgive me if there are some grammar mistake. Comment or ask question if you like. I am open to accept suggestions and will edit this guide if need.

Good luck soldiers.