Here is the full list of all 29 TENGAI achievements.
Clear the stage without destroying any enemies.
Watch the ending with SHO
Watch the ending with MIKO
Stage 7 clear
Stage 6 clear
Increased life
Obtain more than 50 bonus items
Stage 5 clear
Stage 4 clear
Collect maximum quantity of bomb (default setting)
Stage 3 clear
Stage 2 clear
Stage 1 clear
Upgrade the shot until maximum
Watch the ending with JUNIS
Watch the ending with TENGAI
Watch the ending with AINE
Watch the ending with KATANA
Watch the ending without continuing in EASY mode
Watch the ending without continuing in NORMAL mode
Watch the ending without continuing in HARD mode
Watch the ending without continuing in VERY HARD mode
Scored 1,000,000 with JUNIS
Scored 1,000,000 with TENGAI
Scored 1,000,000 with SHO
Scored 1,000,000 with MIKO
Scored 1,000,000 with AINE
Scored 1,000,000 with KATANA
Unlock all achievement