More of a guide this would be some useful tips I found when getting HARDCORE and SPEEDRUN:
- You can pause and abort mission at any time (except for mission VI) before losing your last life and get back to the selecting menu with all the lives, weapons and time you had before starting the mission for the first time. This will grant you the chance of redoing a mission over and over again until you master it without worrying too much about the time. I would recommend restarting the mission if you are above this "par" times I was doing before getting the achievement:
I: 5 min
II: 6-8 min
III: 6-8 min
IV: 6-8 min
V: 8-10 min
VI: 6-8 min
- Always try and get the Defense (Green D) robot. This will grant you 2 extra hits which are basically 2 extra lives for the mission and you can even carry it to the next mission.
- The only time for using other robots would be the Speed (Blue S) robot to get some high extra lives, but it might be even riskier to try and get those rather than just keep advancing on the level.
- Use weapons wisely:
Main gun: great reach and accuracy for distant enemies.
Whip: great anti-infantry in close range. Main weapon for Boss I, mini bosses in mission II and III.
Grenade launcher: destroyer of boss III, super effective against "helicopters", aim for the engine. Also highly effective against mini bosses in mission IV and the first two in mission V.
Charged laser: destroyer of bosses II, and IV, as well as the last mini boss in mission V.
- In risky areas (such as second part of mission V) change to the main gun to avoid losing weapons.
- Once you get to mission VI, kill the first two mini bosses using any weapon (I ended up using the main gun) and once you are facing the final door take a deep breath and focus. If you're facing the final boss with less than 3 lives let him kill you asap so you don't lose your time only to be killed by the last mirror character. Use one credit instead, get the extra life on the ceiling and the Defense robot so that, even when only using the main weapon, you will have 4+2 lives in hardcore or 6+2 in normal. I can only wish you luck here and encourage you to learn the patterns so you only lose lives when facing the mirror characters at the end of each geometry psychedelic section.