[Solitaired]

Here's some tidbits about the executions from the visual fan book.

Kuwata Leon:
The game's staff was sick of his design and personality. Hence, he was picked as the first to be executed. 11037 baseballs were fired. Monokuma made sure that they do not hit the heart area to avoid immediate death.

Oowada Mondo:
The truth behind the butter: He died when the veins in his head burst, and his brain juices exploded. The brain juice and fats became the butter. The rest of the body became plastic, which is used to make the container. The electric shocks prevented him from fainting during the process. Inside the morgue container lies an empty plastic container. Monokuma ate all the butter. Also, apparently the motorcycle he was on was made by a student called Souda Kazuichi.

Yasuhiro Taeko:
A Marie Antoinette style burning - an ending of her dreams. The firetruck is meant for her to despair from not having her dreams fulfilled. Monokuma quenching the fire at the end shows that her hopes are extinguished.

Alter Ego:
Decimation of a laptop = Making real life computer addicts feel despair when they imagine their own keyboards being crashed.
Note: Alter Ego commented that it tickles when Naegi typed his conversation with him. So...

Naegi Makoto/Kirigiri Kyoko:
Naegi/Kirigiri was not bounded to their seats. So they have the chance to escape. But they could not do so as they are in class. An allusion to how a typical student will not suddenly stand up from their seat during class when not called upon. The detention block symbolizes heavy pressure that students faced. And in Japanese, detention - 補習 means 知識を頭に叩き込む, driving knowledge into the head.

Enoshima Junko:
At the very last second, the detention block paused for a moment. At this point, there is a change in Enoshima Junko's expression. This is her getting bored of being executed, just as she is bored with her personalities, her life, everything. This is in contrary to what many gamers thought of : that it is to let her think that she might not be executed.