This is just a placeholder, ok? I'll enhance it for the full release.

Fonts

• 8bit operator JVE (textboxes)
• DotumChe (speech bubbles (not shown), labels)
• Undertale Sans and Undertale Papyrus from here

I modified all of these in FontForge to make them more monospaced. I also fixed the shapes of some Sans and Papyrus glyphs and added a few bonus glyphs to 8bit operator.

Reference

• Undertale Text Project
• maxdefolsch's spreadsheet (haven't used it for this version yet but it'll help with the labeling)

Other

• UndertaleModTool: for decompiling the source code, absolutely essential
• UNDERTALE: cool game, 8/10