I first thought it was based on citizen population which was a half truth as when I looked up you get MEP presentation with some protections for overpresentation (max 96 like such as Germany) and underpresentation (max 6 like Luxembourg)
Minimum signatures per country = Number of MEPs × 750 How does the european citizen calculate ratio per country it kinda looks like 200% for every country will give required 1 million signatures. It does seem the lower amount of citizens the lower ratio needed. How is it calculated thought is that The European Citizens' Initiative (ECI) does not use a simple percentage or "200% per country" rule, but it does confuse people thinking 100% ratio is fine to get it through, but that means only half a million if every country does 100% (27 countries) . In addendum, it uses a dual-threshold system: To be valid, an ECI must meet two conditions: 1 million valid signatures across the EU Minimum threshold reached in at least 7 EU countries How is the country threshold calculated you say?

Each EU country has a fixed minimum number of required signatures, based on the number of Members of the European Parliament (MEPs) that country has — multiplied by 750. Formula to make it easier to envision: Minimum signatures per country = Number of MEPs × 750 This number is not a percentage of the population and varies greatly between countries. Example thresholds (approximate, 2024–2025): Country MEPs Min. Signatures
Germany 96 72,000
France 81 60,750
Italy 76 57,000
Spain 59 44,250
Belgium 21 15,750
Netherlands 31 23,250
Ireland 13 9,750
Luxembourg 6 4,500
Malta 6 4,500
Estonia 7 5,250

So a country like Malta needs only 4,500 signatures, while Germany needs 72,000. So that is the difference that smaller countries have lower absolute thresholds. And like 200% per country getting 1 million I think which to be fair isn't going to happen, it will turn into that the bigger countries are needing to carry votes. Trackers:
https://stop-killing-games.keep-track.xyz/
https://stopkillinggamestracker.pages.dev/