Here are the corrections needed for each sentence:

13. **normal** should be corrected to **normally**. (Adverb form needed)

14. **a little too** should be corrected to **a little too small** (This phrase is repetitive; "too" is sufficient without "a little")

15. **is moderner** should be corrected to **is more modern**. (Comparative form requires "more" for two-syllable adjectives)

16. **playing** should be corrected to **play**. (The gerund form is unnecessary here; infinitive form is needed)

So the corrections are:
13. normal → normally
14. a little too → too small
15. moderner → more modern
16. playing → play