Everyone who has watched this probably agrees that a feature film would've been very cool. This film's animation is very well done and the atmosphere is very beautiful. Now what really makes this movie good is that it feels like an old 1950s-60s Kaiju movie. The plot is simplistic, the monster is powerful, and some guy dies being the hero. This film even follows some of the same elements like cheesy music, overly exaggerated title sequence, space is blue in this movie (like in old Kaiju films) there is even a moth in this movie that has some emphasis (probably a reference to Mothura) and there are many others.
Being a monster movie fan I couldn't resist watching this. The main reason I wish it were feature length is that it really brought me back to the originals, and yet it felt better. The classics were good, but they were kind of annoying. The difference with this movie is that it wasn't annoying. Even the human scenes. The atmosphere was so good that you could imagine you were there. The monster is pretty cool and the three tentacles remind me a little bit of King Ghidorah. Also his main attack which are these lightning rays look very similar to Ghidorah. When he fires them the explosions and all look very familiar, and the explosions even do some of the goofs that the originals had like being able to see through them. You may notice there are no people during the action, which is like the classics since it was all done with toys. The weapons are all from the 60s which is again perfect.
This is an enjoyable film, but I wish it were feature length or at least one hour long. 23 minutes really isn't enough. One gripe is that the music does good at being cheesy, but remember in Godzilla the music isn't really cheesy and it is epic at times. This film however does only cheesy music which kind of ruined the mood. Still good.