After grinding the story mode enough times, spent 2 hours to clear extra with all 3 characters, learning routing and getting 999+ dyes in a run. Achievements gotten.
All achievements gotten. 3 hours for Cancer Speed, the rest of the time was spent grinding attempts in order to get powerful enough to... no-hit a specific boss.
Still missing wins with a few characters but that isn't an achievement.
First easy mode with no upgrades, then hard run clear, then hard run with 50k gold. Then finally the challenges. Did not have to grind because I could simply do challenge 4 again.
While grinding for Version B medals, got the 2-ALL with Sadahl, the one character I was missing his ending and better than Loop at certaing things. Then grinded a bit more and got the medals.
Beat the game with a continue, then again (both on hard) with 1.5M points. Then grinded the start of level 5 for the 10k kills, killing my character to force end the run because it doesn't save otherwise until the end of the level.
Played the game a bit. Watched a video, then did a full game clear, in 1 hour of ingame gameplay. Then spent the rest of the time doing the challenges for RetroAchievements in level order, like timeouting bosses nmnb and beating stages separately nmnb. I spent a similar-ish time on everything, with the final level being a bit more difficult (and with less restrictions!)
Beat the game on normal, then arcade and with its TLB all in one credit. Thanks, Fire Arrow X ship. (2h 12m) ----------------------------------------------- Grinded the rest of the achievements.
Got a Desperate (hardest difficulty) clear. The game has no continues. It also crashed before I could save the replay. (2h 16m) ------------------------- Cleared the extra on first try then did again a Lunatic 1CC without a crash.