score:3
If you are Croatian citizens then yes, you can do this. A valid national ID card is sufficient for any EU citizen to enter any other EU country.
This is specified in directive 2004/38/EC. Article 5(1) says:
Article 5
Right of entry
Without prejudice to the provisions on travel documents applicable to national border controls, Member States shall grant Union citizens leave to enter their territory with a valid identity card or passport and shall grant family members who are not nationals of a Member State leave to enter their territory with a valid passport.
No entry visa or equivalent formality may be imposed on Union citizens.
(emphasis added)